The invention relates in general to munitions and in particular to shaped charge warheads.
Shaped charge warheads are used in military applications for the defeat of armored targets. These devices comprise a shaped charge liner (typically conical in shape) that is backed by a high explosives charge. When the explosive is detonated, the expanding gasses collapse the liner onto itself forming a high-velocity forward moving jet. As the detonation wave continues to sweep forward, more of the liner is collapsed and fed into the jet. Since the jet tip moves faster than the tail, the jet stretches as it moves down the shot line—the longer it stretches, the deeper the penetration.
Wave shaping devices have long been used to alter the collapse dynamics of the shaped charge liner by changing the incident angle and liner sweep velocity of the impinging detonation wave. By directing the detonation front to the warhead periphery, parameters such as jet tip velocity, accumulated jet mass, jet length, and jet breakup times can be altered. In particular, wave shaping can be used to reduce head height (distance between liner apex and detonator) while maintaining penetration and thus reducing the overall length of a warhead.
Since World War II, traditional wave shaping has been accomplished through mechanical means by inserting a barrier type device in the detonation path to divert the wave to the outside edge of the warhead. Wave shapers can significantly increase penetration performance against armor. In addition, the blast output from the contained explosive in the warhead can also be used against other targets such as personnel, light vehicles, helicopters, or structural targets such as buildings and bunkers. However, for blast effects, the wave shaper volume is parasitic in nature since they are generally made from inert materials. Thus, they provide no added explosive output (non-energy contributing). By replacing these inert wave shaping materials with low-reaction rate, high-blast producing reactive materials, the wave shaping volume can be used to produce increased lethal blast effects that are not achievable in current shaped charge warheads.
The explosive output of a reactive wave shaper can be differentiated between blast and incendiary effects. Incendiary devices are designed to start fires and are characterized by high heat output and light. These types of materials provide increased temperature on the target and are primarily good for igniting combustible materials such as diesel fuel or timber structures. U.S. Pat. No. 5,259,317 issued on Nov. 9, 1993 shows a hollow charge having a wave guide made of an incendiary material.
Blast output may be characterized by the ability of the system to transfer blast energy to displace a target and perform work. The application of this force over time produces a significant impulse that is capable of knocking down buildings, damaging structures and causing lethality due to the blast overpressure. The ability to create an increased pressure impulse is the desired trait for a blast material. Shaped charges having wave shapers formed from low-reaction rate, high-blast producing reactive materials are not known.